Color image sensors comprising a network or an array of pixels formed in a semiconductor layer having a first side, called a front side, coated with an interconnection structure and having a second side, called a back side, intended to receive an illumination, are known. In such color image sensors, each pixel is separated from the adjacent pixels by insulating structures extending vertically between the front side and the back side of the semiconductor layer. Each pixel is topped with a color filter arranged above the back side of the semiconductor layer. The color filters of adjacent pixels are positioned side by side. To concentrate in each pixel the received light intensity, each color filter is currently topped with a microlens.
A disadvantage of such color image sensors is that a light ray having at least partially crossed the color filter corresponding to a given pixel may sometimes reach a neighboring pixel. Another disadvantage of such sensors is that the materials forming two adjacent filters of different colors may mix.